【摘要】 基于密度泛函理论系统下的第一性原理,对纯ZnO,Cd掺杂ZnO,Cu掺杂ZnO,Cu-Cd共掺杂以及Cu-2Cd共掺杂ZnO五个超晶胞模型分别进行几何结构优化;计算和分析了各体系的晶胞结构,能带结构,态密度以及光学性质方面的介电函数虚部,吸收率和反射率.研究结果表明:Cu,Cd单掺杂可提高ZnO的载流子浓度,改善ZnO的导电性;但Cu和Cd共掺杂ZnO时,体系的E更低,状态更加稳定.光学性质方面:Cd掺杂时,紫外区边发生红移,吸收系数略增大;当Cu单掺以及Cu和Cd共掺杂ZnO,体系在可见光和紫外波段吸收系数明显增大,使得ZnO光催化性能提升;结合Cu和Cd单掺杂的特性,说明当Cu和Cd共掺杂ZnO时,控制Cd的掺杂浓度,半导体会产生不同的透光率,因此控制Cu-Cd的比率来掺杂ZnO可用于制作不同效率的光透性器件.更多还原

【Abstract】 Based on the primary principle of density functional theory(DFT) system, five super-cell models of the pure ZnO, Cd doped ZnO, Cu doped ZnO, Cu-Cd co-doped ZnO, and Cu-2 Cd co-doped ZnO, were optimized respectively for their geometric structure. The cell structure, energy band structure, state density, and their optical properties such as the imaginary component of dielectric function, absorption rate and reflectivity of each system were calculated and analyzed. The investigation result showed that the single doping of Cu or Cd could increase the carrier concentration of the ZnO and make the conductivity of ZnO improved. Never the less, in the case of Cu-Cd co-doping, the state of ZnO system would be more stable due to lower E. In connection with optical properties, the Cd-doping would make red shift of the edge of the ultraviolet region and the absorption would be slightly enhanced. When the ZnO was doped by Cu and Cu-Cd co-doped, the absorption coefficient of the system at the visible light and ultraviolet band would increase remarkably, making the photocatalytic activity of ZnO enhanced. When the characteristics single doping of ZnO with Cu and Cd was taken into consideration, the Cu-Cd co-doping of ZnO would make the semiconductor produce different transmittance if the doping concentration of Cd was controlled. So that the transparent devices with different efficiency could be propered by managing the doping of ZnO with different ratio of Cu-Cd.更多还原